Aerial payload delivery systems, also known as ram canopy parachute systems, offer the capability to deliver large payloads and or people to undeveloped or inaccessible locations. The canopies in these systems are well known and often referred to as parafoils from which payloads may be suspended via rigging lines or control lines. The parafoils are generally constructed of an upper canopy and a lower canopy connected by a cell structure, also known as ribs, that is well known in the art. The flexible parafoils provide aerodynamic lift by virtue of shape of the canopy and an alteration in the shape can greatly affect the directionality of the parafoil.
Several autonomous guided systems have been developed that use trailing edge brake deflection for lateral control by altering the shape of the parafoil that have been shown to increase landing accuracy. The control of internal air, referred to as ram air, vented through the upper surface of the canopy creating aerodynamic spoilers has been shown to improve glide slope control. The released ram air is called bleed air. Such known autonomous systems have involved altering the control lines from a device, such as an actuator, on or within the payload to alter the shape of the parafoil. These known control lines create aerodynamic drag and can become tangled or damaged upon deployment resulting in loss of control and landing accuracy. Known systems have not provided the necessary accuracy, have been unsuccessful, and distort the canopy causing it to collapse.
U.S. patent application Ser. No. 14/479,530, the disclosure of which is incorporated by reference describes the use of an actuator embedded within the parafoil that controls a series of slits or spoilers in the upper surface of the canopy releasing a portion of the ram air inflating the parafoil. Opening and closing the spoilers by actuation alters the amount of bleed air and changes the forces and moments acting on the parafoil in a consistent manner such that it can be used for flight control. Accordingly, a method to increase the amount of bleed air without altering the aerodynamic efficiency of the canopy would increase glide slope control and landing accuracy.